During cardiac operations with extracorporeal circulation and CPB, the heart and lung function is artificially replaced by a heart-lung machine. This device receives the venous blood of the patient and delivers it (through a roller or centrifugal pump) to an oxygenator which provides the carbon dioxide (CO2) clearance and the oxygen (O2) supply to the patient, by means of a trans-membrane exchange between blood and a gas flow (oxygen and air at variable concentrations).